The Rudd government believed mandating training for installers would create unnecessary red tape in its home insulation scheme, an inquiry has heard.

It put job creation and stimulating the economy ahead of the safety of workers, disregarding an early recommendation that all installers be trained.

The $20m royal commission into the scheme, which has been blamed for four deaths, on Thursday heard how safety training was scaled back to only include supervisors.

Despite this, there was never a requirement for supervisors to be on site when workers were installing insulation.

A senior Environment Department staffer, Ross Carter, told the inquiry that training for installers was initially part of the scheme but the government didn’t want to add additional layers of regulation.

The commissioner, Ian Hanger, asked what discussions gave rise to the removal of installer training.

“The discussion that I recall was that the requirements were going to be a barrier for entrants into the program, and that wasn’t in keeping with the government’s intention of it being readily available,” Carter replied.

Installers only needed a white card, which is a basic general safety induction, before getting into ceilings.

Carter said the government had believed installing insulation was “low skill” work and the existing safety framework was adequate.

The inquiry also heard about how the government moved away from a regional delivery model, which had provisions for training, to a much larger one which ended up involving 10,000 organisations.

The original model was ditched after a March 2009 meeting involving staff from the co-ordinator general’s office and the former senator Mark Arbib, who was charged with co-ordinating government stimulus programs.

The inquiry was also told on Thursday that public servants were working at “110% capacity” when then prime minister Kevin Rudd’s department told them to devise the insulation program in early February 2009.

They then worked around the clock, on weekends and as late as 10pm during the week, to devise the scheme so it was ready by the 1 July 2009 deadline the government set.

The royal commission, which began in Brisbane on Monday, has heard how two senior Environment Department staffers were given just two days to cost the scheme.

It has also been told bureaucrats were repeatedly warned installers would die on the job if safety issues weren’t addressed.

Queenslanders Matthew Fuller, Rueben Barnes and Mitchell Sweeney, and Marcus Wilson from New South Wales, all died working under the scheme, which has also been blamed for one serious injury and hundreds of house fires.